1. Field of the Invention
The present invention relates to compression devices for living being, wound around a wrist, an upper arm, or a similar site to be measured, to exert pressure thereon for measuring blood pressure.
2. Description of the Background Art
A conventional compression device for living being of the above type is such as shown in FIG. 7. Compression device 30 for living being is formed of an outer cloth 31 and an inner cloth 32 together forming a belt-like bag, an air bag 33 provided internal to the belt-like bag, and an elastic curved plate 34 arranged outwardly of air bag 33 to prevent air bag 33 from expanding outwards, and also elastically holding a predetermined curvature. Outer cloth 31 and inner cloth 32 are provided with hook and loop fasteners 35 and 36, respectively, for fastening device 30 wound around a site to be measured.
A site to be measured significantly varies in size from individual to individual and for example some people have a thin wrist and other people have a thick wrist and there can be a significant difference therebetween. In the conventional compression device 30 is crucial the shape of elastic curved plate 34: If elastic curved plate 34 previously adapted to fit a thick site to be measured is used on a thin site to be measured a gap is formed therebetween and there does not build a force to hold the site to be measured and to fill the gap air bag 33 needs to further expand. As such, elastic curved plate 34 is typically adapted to fit a thin site to be measured.
In doing so, if elastic curved plate 34 is adapted to have a length corresponding to the circumference of an elliptic, thin site to be measured (wrist) 20, as shown in FIG. 8, elastic curved plate 34 fits along site to be measured 20. If this elastic curved plate 34 is applied to a person having a thick site to be measured 20, as shown in FIG. 9, elastic curved plate 34 would have an end 30b readily ingrowing into site to be measured 20 and thus causing pain to the person wearing the device. This pain increases if site to be measured 20 is thicker.
If elastic curved plate 34 is adapted to fit a thin site to be measured (wrist) and also have a length corresponding to half the circumference of an elliptic site to be measured 20, as shown in FIG. 10 (see its state before use), a person with a thin site to be measured 20 would wear the device with elastic curved plate 34 fitting site to be measured 20, as appropriate. However, if a person with a thick site to be measured 20 would wear the device then elastic curved plate 34 at an end 30a in particular exerts a force acting in a direction causing elastic curved plate 34 to come off, as shown in FIG. 11. As such, elastic curved plate 34 readily comes off site to be measured 20. Thus there does not occur a force to hold site to be measured 20 and device 30 can hardly be wound around site to be measured 20 closely.
As described above, elastic curved plate 34 adapted to fit a thin site to be measured 20 has the disadvantages as described above when it is applied on a thick site to be measured 20, and it is thus difficult to apply compression device 30 for living being to sites to be measured 20 of different sizes, as appropriate. Consequently, if device 30 is used with a sphygmomanometer mounted thereon the sphygmomanometer cannot provide a reliable blood pressure measurement.
To overcome this disadvantage, there has been developed an arm band having a bag in the form of a band with an air bag fixed thereto which spirally curves with a plurality of radii of curvature increasing from one side thereof with the air bag fixed thereto toward the remaining portion of the bag and also is elastically deformable, as disclosed in Japanese Utility Model Laying-Open No. 62-6804. With this structure, when it is applied on a thick site to be measured it does not have an end ingrowing into the site to be measured. However, the radius of curvature gradually increased prevents the band from exerting force enhanced to sufficiently grip the thick site to be measured when the band is applied on the thick site to be measured. This prevents the band from temporarily holding the site to be measured closely. As such, the band wound around the site to be measured readily moves, often resulting in inaccurate blood pressure measurement.
To overcome this disadvantage, there has been proposed an arm band using a hinge to allow a curvature corresponding to a superior arc and a curvature corresponding to an inferior arc to have a clamping force, as disclosed in Japanese Patent Laying-Open No. 8-10233. With this method, the arm band applied on a thick site to be measured can exert force enhanced to sufficiently grip the thick site to be measured. However, the hinge is provided in the form of a spring plate or the like and this increases the number of components and the number of fabrication steps and hence the manufacturing cost and it also prevents the arm band from having a simple structure in design.
The present invention contemplates a compression device for living being, simply structured and fitting a site to be measured of any size.
The present invention in one aspect provides compression device for living being, including a fluid bag internal to the compression device, expanding and contracting when the fluid bag receives and discharges fluid, respectively, and an elastic plate formed in one piece and provided internal to the compression device, arranged outwardly of the fluid bag to prevent the fluid bag from expanding outwards, and also elastically holding a predetermined curvature, the elastic plate including a first curvature substantially matching a lateral cross section of a thin site to be measured, a second curvature and a connection connecting the first and second curvatures together, the connection allowing the second curvature to be arranged outwardly of a virtual extension of the first curvature substantially matching the lateral cross section of the thin site to be measured, the second curvature extending inwardly of a virtual extension of the connection extending toward the second curvature.
In this device the elastic plate has the first curvature formed to substantially match a lateral cross section of a thin site to be measured. As such, when the device is applied on a thin site to be measured the device fits the site to be measured closely. In addition, the elastic plate has the second curvature arranged outward by means of the connection and also extending inward from the connection. As such, when the device is applied on a thick site to be measured, (1) a portion of the first curvature closer to an end of the first curvature, (2) a portion of the first curvature adjacent to the center of the first curvature and closer to the connection and (3) an end of the second curvature, a total of three points act to exert force to clamp the site to be measured in three directions. As such, the elastic plate holds the site to be measured with large force and the compression device does not ingrow into the site to be measured and thus fits the site to be measured closely.
It should be noted that in the present description a site to be measured refers to a wrist, an upper arm or a similar site. If a wrist is to be measured, then a thin site to be measured means a wrist having its entire circumference of no more than approximately 16.5 cm. If an upper arm is to be measured, then a thin site to be measured means an upper arm having its entire circumference of no more than approximately 23 cm. A thick site to be measured for a wrist corresponds to no less than approximately 18.5 cm and that for an upper arm corresponds to no less than approximately 27 cm. The virtual extension of the connection curving as seen in lateral cross section means a curvature corresponding to an extension approximating to the curvature of the connection, and the virtual extension of the connection formed in a straight line means an extension of the straight line.
The present invention in one aspect provides the compression device for living being, wherein the second curvature is desirably more distant inward from the virtual extension of the connection as the second curvature extends farther away from the connection.
Thus, the second curvature is bent at the connection inward at a large angle. As such, when the compression device is applied on a thick site to be measured, it can exert force toward the center of the site to be measured as seen in cross section. Thus, it can exert force enhanced to sufficiently grip the site to be measured to facilitate temporarily holding the site to be measured, as appropriate.
The present invention in one aspect provides the compression device for living being, wherein when applied on a thick site to be measured the second curvature has a portion in contact with the thick site to be measured by at least a predetermined length to prevent the second curvature from having an end ingrowing into the thick site to be measured.
Since the second curvature has a portion of at least a predetermined length contacting the site to be measured, it does not ingrow into the site to be measured to prick the site to be measured. This ensures a further sufficient level of force gripping the site to be measured.
The present invention in one aspect provides the compression device for living being, wherein the first curvature is formed of a center, a portion of the first curvature adjacent to the center and closer to an end of the first curvature and a portion of the first curvature adjacent to the center and closer to the connection, and when applied on a thin site to be measured the portion of the first curvature closer to the end of the first curvature and the portion of the first curvature closer to the connection cooperate to produce elasticity toward a center of the thin site to be measured, as seen in lateral cross section, to clamp the thin site to be measured.
As such, the first curvature is sufficient to exert force to sufficiently grip a thin site to be measured in applying the compression device on the thin site to be measured. As such, while the second curvature and the connection are prevented from ingrowing into a thick site to be measured, there can be created force enhanced to sufficiently grip the thick site to be measured. Note that while the first curvature is formed to substantially match a lateral cross section of a thin site to be measured, between the elastic plate and the site to be measured there is located an air bag or the like and understandably the first curvature at an intermediate portion thereof provides an widened receiving angle and with elasticity created the compression device is applied on the thin site to be measured.
The present invention in one aspect provides a compression device for living being, wherein when applied on a thick site to be measured, the first curvature elastically deforms to widen an angle formed by the portion of the first curvature closer to the end of the first curvature, the center and the portion of the first curvature closer to the connection, and receiving the site to be measured, and the second curvature contacts the thick site to be measured and elastically deforms to widen an angle formed by the connection and the second curvature with a second connection located therebetween to connect the second curvature and the connection together, to create force exerted in a direction from a surface of the thick site to be measured toward the center of the thick site to be measured, as seen in cross section.
The portion of the first curvature closer to the end of the first curvature and that of the first curvature closer to the connection cooperating to clamp the aforementioned branch point, and the second curvature can create force to grip a site to be measured in three directions. The second curvature exerts force directed toward the center of the site to be measured to prevent the end from ingrowing into the site to be measured.
The present invention in a second aspect provides a compression device for living being, including a fluid bag internal to the compression device, expanding and contracting when the fluid bag receives and discharges fluid, respectively, and an elastic plate formed in one piece and provided internal to the compression device, arranged outwardly of the fluid bag to prevent the fluid bag from expanding outwards, and also elastically holding a predetermined curvature, the elastic plate including a first curvature substantially matching a lateral cross section of a thin site to be measured, a second curvature and a connection connecting the first and second curvatures together, the connection as seen in cross section being either one of a linear connection provided in a straight line and an arcuate connection including a curvature concave outward.
Providing the connection formed as described above can reduce the circumference of the second curvature and accordingly increase the circumference of the first curvature and also increase the gradient at which the second curvature extends from the connection inwards. As such, when the compression device is applied on a thick site to be measured, the force that the second curvature exerts on a surface of the thick site to be measured can be directed to the center of the site to be measured. Furthermore, the arcuate connection having an arcuate portion concave outward and the linear connection allow the second curvature to have a higher level of elasticity for restoration than a connection having only an arcuate portion convex outward. As such, not only can the force exerted to grip a site to be measured be directed to the center of the site to be measured but it can also be increased in magnitude.
The present invention in the second aspect provides the compression device for living being, wherein the first curvature is arranged along at least half of an entire circumference of the lateral cross section of the thin site to be measured. Furthermore, the first curvature is arranged along at least 70% of an entire circumference of the lateral cross section of the thin site to be measured.
Configuring the connection as described above can increase the circumference of the first curvature. As such the first curvature is sufficient to exert force enhanced to sufficiently grip and thus fit a thin site to be measured closely. Furthermore, if the compression device is applied on a thick site to be measured, the first curvature, with an intermediate portion thereof spaced from the thick site to be measured by at least a predetermined distance, can clamp the thick site to be measured. As such, it is not necessary for the intermediate portion of the first curvature to approach the site to be measured to significantly increase the site to be measured receiving angle to result in the intermediate portion of the first curvature exceeding its limit of elasticity. As such, the compression device can exert force enhanced to sufficiently grip the thick site to be measured easily and thus obtain durability to be used repeatedly. Such strong gripping force and durability as above can be obtained by arranging the first curvature along at least 50% of the circumference of the thin site to be measured. Furthermore to ensure such effects the first curvature desirably has a length along at least 70% of the circumferential of the thin site to be measured.
The present invention in the second aspect provides the compression device for living being, wherein the first curvature includes both ends clamping the site to be measured and a center located between the both ends and larger in thickness than the both ends.
The center increased in thickness can provide increased elasticity when the site to be measured receiving angle is widened. As such there can be provided an increased level of elasticity for restoration clamping the site to be measured.
The present invention in the second aspect provides the compression device for living being, wherein when applied on a thick site to be measured the second curvature has a portion of at least a predetermined length exerting force directed from a surface of the thick site to be measured toward a center of the thick site to be measured as seen in lateral cross section.
As such, when the compression device is applied on the thick site to be measured the second curvature does not have an end thereof ingrowing into the thick site to be measured and also cooperates with the first curvature to create a level of force that can sufficiently grip the site to be measured.
The present invention in a third aspect provides the compression device for living being, including a fluid bag internal to the compression device, expanding and contracting when the fluid bag receives and discharges fluid, respectively, and an elastic plate formed in one piece and provided internal to the compression device, arranged outwardly of the fluid bag to prevent the fluid bag from expanding outwards, and also elastically holding a predetermined curvature, the elastic plate including a first curvature substantially matching a lateral cross section of a thin site to be measured, a second curvature and a connection connecting the first and second curvatures together, when applied on a thick site to be measured the second curvature extending along a surface of the thick site to be measured and cooperating with the first curvature to create force to hold the thick site to be measured.
As such, the second curvature does not have an end thereof ingrowing into the site to be measured, while it can exert elasticity for restoration toward the center of the site to be measured as seen in lateral direction and also cooperate with the first curvature to create force enhanced to sufficiently grip the site to be measured.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.